Frequency mixers are used to mix two input signals in order to generate a new signal at a new frequency. A frequency mixer may input signals at two frequencies f1, f2, and mix them to create two new signals, one at the sum f1+f2, and the other at the difference f1−f2. Typically, only one of these new signals is used. For example, a frequency mixer in a radio receiver may be used to down-shift or frequency translate an incoming signal at a radio frequency by the frequency of an oscillator signal. The radio frequency signal may occupy a frequency range, in which case the frequency mixer may shift the frequency range of the radio frequency signal by the frequency of the oscillator signal. Frequency mixers can be used in radio signal receivers and transmitters, but their use is not limited thereto.